(1) Field of the Invention
The invention relates to a lampshade structure for LED (light emitting diode) lamps, and more to the lampshade structure that provides a semi-reflection portion for redirecting part of the incident rays to other portion of the lampshade so as to transform the LED lamp into an omni-directional light bulb apparatus.
(2) Description of the Prior Art
In the art of the omni-directional illumination, the common incandescent lamp who provides an illumination pattern almost in all directions dominates the market for decades. Yet, the conventional incandescent lamp has an untouchable drawback in energy-consumption, and this is the problem that draws intensive concern in considering almost all electric and electronic apparatuses nowadays. Inevitably, the conventional incandescent lamps and light bulbs need to be replaced as soon as possible in all comprehensive illumination applications.
The development of light emitting diodes (LED) featured in power-saving and more environment-friendly seems to provide a resort to resolve the energy-consumption problem in the illumination industry. However, the limited illumination pattern of the LED still poses a viewing-angle problem for many lighting applications. Commonly, the viewing angles of the LEDs are limited to 30-120 degrees, but the intensity is reduced up to 50% at the extremes of each illumination pattern. Such a characteristic of the LED illumination hinders the possibility of a whole-scale replacement of the conventional incandescent lamps.
Nevertheless, there are still various ways to modify the illumination pattern of the LEDs. One of these methods is laid on the diffusion property of lights by using a frosted or diffraction-style lens, canopy or lampshade to cover the LEDs of the lamp. This method is successful to some degrees but may attenuate the total light to make darker of the lamp.
Another technique is to mount many LEDs to form a lighting pine cone in the lamp device for providing lights in all directions. Yet, such an approach is costly and difficult to manufacture, and also induces always a heat-dissipation problem which may be too big and expensive to be resolved.
Definitely, in the development of using LEDs in omni-directional illumination, efforts to provide a less-expensive, sufficient illumination and less heat-accumulated LED lamp are surely and widely welcome to the world.